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Specialist assays and profiles


Factor assays and related investigations

Factor assays available:

  • II, V, VII, VIII, IX, X, XI, XII, HMWK, Prekallikrein
  • Chromogenic FVIII assay
  • Clotting factor antigen: V, VII, VIII, IX, XI
  • Bethesda assays: VIII, Porcine VIII, IX
  • Inhibitor screening


Results for these tests are available within one week of receipt in the laboratory. HMWK, prekallikrein and clotting factor antigens are performed less regularly and results made available as soon as possible. External service users may contact the laboratory for information regarding result progress. 


Requests for factor assays must be discussed with a consultant of the Centre for Haemostasis and Thrombosis.

Sample requirements

Citrate (blue top tube)
One 4.5 ml citrated sample is sufficient for up to 2 factor or Bethesda assays. Two samples are necessary for more than 2 factor assays or inhibitor screening.

If you have enquiries

Please call 020 7188 2797, Monday to Friday, 9am-5.15pm.